Field of the Invention
The present invention is generally related to an apparatus and method for forming a wave form for a stent. More particularly, the present invention is related to an apparatus and method for forming the wave form from a wire.
Background of the Invention
A stent is typically a hollow, generally cylindrical device that is deployed in a body lumen from a radially contracted configuration into a radially expanded configuration, which allows it to contact and support a vessel wall. A plastically deformable stent can be implanted during an angioplasty procedure by using a balloon catheter bearing a compressed or “crimped” stent, which has been loaded onto the balloon. The stent radially expands as the balloon is inflated, forcing the stent into contact with the body lumen, thereby forming a support for the vessel wall. Deployment is effected after the stent has been introduced percutaneously, transported transluminally, and positioned at a desired location by means of the balloon catheter.
Stents may be formed from wire(s), may be cut from a tube, or may be cut from a sheet of material and then rolled into a tube-like structure. While some stents may include a plurality of connected rings that are substantially parallel to each other and are oriented substantially perpendicular to a longitudinal axis of the stent, others may include a helical coil that is wrapped around the longitudinal axis at a non-perpendicular angle.
A stent that includes a helical coil may be formed from a single wire that includes a wave form that is configured to allow the stent to radially expand. In view of the small size of the stents, it may be difficult to form a stent from a single wire while controlling the wave form so that individual waves may vary in size and shape. Further, accurately and uniformly bending the stent wire without adversely deforming the stent wire is difficult. Accordingly, there is a need for apparatus and methods for accurately and uniformly forming a wave form in a stent wire such that each wave of the wave form can be individually controlled for size and shape.